It is an amazing and important concept to have one's last wishes in a contract. You have seen a need for such a service. However, there is a current and active platform currently that is doing exactly this, among many other things. The platform is called MyWish (was initially launched as Last Will). On this platform you can create Will contracts wedding contracts, launch airdrops etc. I put some links below. I would strongly suggest that instead of launching another coin, that you look at that platform to see it it satisfies your needs. The MyWish team has also launched Rubic Exchange and Algebra Exchange.
Link to MyWish Bitcointalk thread
Link to Mywish Website